Nasal Allergy Medications (cont.)

Omudhome Ogbru, PharmD

Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

Antihistamines perform best when taken regularly or before an allergic
reaction begins. The second generation antihistamines may take up to an hour or
more to become effective. They should be taken well before an expected allergic
exposure, such as a visit to a friend who has a cat, and that the person may be
allergic to cat dander.

What are common side effects of antihistamines?

Since the first generation antihistamines can penetrate the brain tissue,
they generally cause more side effects than the second generation drugs, which
usually cannot enter the central nervous system. Drowsiness is the most
noticeable side effect, but this is sometimes desirable. For example, it may be
useful when nighttime symptoms prevent restful
sleep.
During the day, however, this effect can cause problems.

Be cautious about driving a car or operating a machine when using OTC
antihistamines. Do not take any tranquilizers or drink alcohol along with these
drugs. The combination may promote more drowsiness. Also, a person should check
with the doctor before taking an antihistamine if they have
glaucoma
or thyroid, heart, or prostate problems because the antihistamines may make
these problems worse.

The first generation antihistamines may also cause troublesome
anticholinergic effects such as
heart palpitations, difficulty urinating,
constipation, dry mouth, and nervousness. These side effects usually occur
when the medication is taken at higher than recommended doses.

The second generation of antihistamines currently on the market has few, if
any, significant side effects at the recommended doses.

Antihistamines may be used for nasal symptoms in patients with
asthma.
It was previously thought that these drugs would dry up the airways in the
patient's bronchial tubes and aggravate the asthma. However, there is no good
evidence supporting this notion. Improving nasal allergy symptoms may benefit
patients with asthma.

What are decongestants?

Nasal stuffiness or congestion occurs as a result of swelling of the nasal
membranes. Histamine opens the blood vessels and encourages fluid leakage from
them, thereby causing the tissues to become "congested." This reaction reduces
the space inside the nose through which we breathe and results in the typical
"blocked" or stuffy nose. While antihistamines can control many symptoms of
allergic rhinitis, they are not very helpful for treating
nasal congestion once
it has already occurred. At this point, decongestants can be a very useful
addition (see next section).